Yes Its works - I setup the Watch to control both the Apple TV & my Macbook . You also can control other things like TV'v with third party
apps , Theres a pais app that lets you control Directv and entertainment items .

I am using it as the remote for the Apple TV. Please note that your phone has to be using the same wifi as the Apple TV for this to work as the watch remote app is just an extension of your phone at this point. have fun!

Used mine as a remote for my Apple TV yesterday- worked quite well, better in some ways than the original remote (intuitive and Apple TV responds quickly to the inputs from the watch). Obviously near impossible to use for password entry and the like, but the original remote isn't great for that either in my opinion.